This paper presents a partially synchronous BFT consensus protocol powered by BBCA, a lightly modified Byzantine Consistent Broadcast (CBC) primitive. BBCA provides a Complete-Adopt semantic through an added probing interface to allow either aborting the broadcast by correct nodes or exclusively, adopting the message consistently in case of a potential delivery. It does not introduce any extra type of messages or communication cost to CBC. BBCA is harnessed into BBCA-CHAIN to make direct commits on a chained backbone of a causally ordered graph of blocks, without any additional voting blocks or artificial layering. With the help of Complete-Adopt, the additional knowledge gained from the underlying CBC completely removes the voting latency in popular DAG-based protocols. At the same time, causal ordering allows nodes to propose blocks in parallel and achieve high throughput. BBCA-CHAIN thus closes up the gap between protocols built by consistent broadcasts (e.g., Bullshark) to those without such an abstraction (e.g., PBFT/HotStuff), emphasizing their shared fundamental principles. Using a Bracha-style CBC as an example, we fully specify BBCA-CHAIN with simplicity, serving as a solid basis for high-performance replication systems (and blockchains).

翻译：本文提出一种基于BBCA的部分同步BFT共识协议，BBCA是一种经轻量级修改的拜占庭一致广播（CBC）原语。BBCA通过新增探测接口实现Complete-Adopt语义，允许正确节点中止广播，或在可能交付时专门一致性地采纳消息，且不引入任何额外消息类型或通信开销。将BBCA融入BBCA-CHAIN后，可在因果有序区块图链式骨干上直接提交，无需额外投票区块或人工分层。借助Complete-Adopt语义，底层CBC提供的额外知识完全消除了流行DAG协议中的投票延迟。同时，因果排序允许节点并行提议区块以实现高吞吐量。由此，BBCA-CHAIN弥合了基于一致广播构建的协议（如Bullshark）与无此类抽象协议（如PBFT/HotStuff）之间的差距，突显其共有的基本原理。以Bracha风格CBC为例，我们以简洁方式完整规范了BBCA-CHAIN，为高性能复制系统（及区块链）提供了坚实基础。